Within five years, officials expect to identify about 80 percent of the Oklahoma crew members still considered missing.

The military says it started the project because advances in forensic science and technology are improving the ability to identify remains.

On Monday, officials exhumed the last four of 61 caskets containing unknown people from the Oklahoma. Many of the caskets include the remains of multiple individuals.

Families will have the option of receiving remains as they are identified, or waiting until the agency has more pieces of a body or even a complete skeleton. Navy casualty officers will let families know their options.

Altogether, 429 men on board the World War II battleship were killed. Only 35 were identified in the years immediately after.

Identification work will be conducted at agency laboratories in Hawaii and Nebraska. DNA analysis will be conducted at the Armed Forces DNA Identification Laboratory at Dover Air Force Base in Delaware.

More than 2,400 sailors, Marines and soldiers were killed in the attack on Pearl Harbor. The Oklahoma's casualties were second only to the USS Arizona, which lost 1,177 men.